linux/kernel/trace, branch v4.3

tracing: Do not allow stack_tracer to record stack in NMI

2015-10-21T01:52:23Z

The code in stack tracer should not be executed within an NMI as it grabs spinlocks and stack tracing an NMI gives the possibility of causing a deadlock. Although this is safe on x86_64, because it does not perform stack traces when the task struct stack is not in use (interrupts and NMIs), it may be an issue for NMIs on i386 and other archs that use the same stack as the NMI. Signed-off-by: Steven Rostedt

tracing: Have stack tracer force RCU to be watching

2015-10-20T15:38:08Z

The stack tracer was triggering the WARN_ON() in module.c: static void module_assert_mutex_or_preempt(void) { #ifdef CONFIG_LOCKDEP if (unlikely(!debug_locks)) return; WARN_ON(!rcu_read_lock_sched_held() && !lockdep_is_held(&module_mutex)); #endif } The reason is that the stack tracer traces all function calls, and some of those calls happen while exiting or entering user space and idle. Some of these functions are called after RCU had already stopped watching, as RCU does not watch userspace or idle CPUs. If a max stack is hit, then the save_stack_trace() is called, which will check module addresses and call module_assert_mutex_or_preempt(), and then trigger the warning. Sad part is, the warning itself will also do a stack trace and tigger the same warning. That probably should be fixed. The warning was added by 0be964be0d45 "module: Sanitize RCU usage and locking" but this bug has probably been around longer. But it's unlikely to cause much harm, but the new warning causes the system to lock up. Cc: stable@vger.kernel.org # 4.2+ Cc: Peter Zijlstra Cc:"Paul E. McKenney" Signed-off-by: Steven Rostedt

Merge tag 'trace-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2015-09-08T21:04:14Z

Pull tracing update from Steven Rostedt: "Mostly this is just clean ups and micro optimizations. The changes with more meat are: - Allowing the trace event filters to filter on CPU number and process ids - Two new markers for trace output latency were added (10 and 100 msec latencies) - Have tracing_thresh filter function profiling time I also worked on modifying the ring buffer code for some future work, and moved the adding of the timestamp around. One of my changes caused a regression, and since other changes were built on top of it and already tested, I had to operate a revert of that change. Instead of rebasing, this change set has the code that caused a regression as well as the code to revert that change without touching the other changes that were made on top of it" * tag 'trace-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ring-buffer: Revert "ring-buffer: Get timestamp after event is allocated" tracing: Don't make assumptions about length of string on task rename tracing: Allow triggers to filter for CPU ids and process names ftrace: Format MCOUNT_ADDR address as type unsigned long tracing: Introduce two additional marks for delay ftrace: Fix function_graph duration spacing with 7-digits ftrace: add tracing_thresh to function profile tracing: Clean up stack tracing and fix fentry updates ring-buffer: Reorganize function locations ring-buffer: Make sure event has enough room for extend and padding ring-buffer: Get timestamp after event is allocated ring-buffer: Move the adding of the extended timestamp out of line ring-buffer: Add event descriptor to simplify passing data ftrace: correct the counter increment for trace_buffer data tracing: Fix for non-continuous cpu ids tracing: Prefer kcalloc over kzalloc with multiply

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2015-09-03T15:08:17Z

Pull networking updates from David Miller: "Another merge window, another set of networking changes. I've heard rumblings that the lightweight tunnels infrastructure has been voted networking change of the year. But what do I know? 1) Add conntrack support to openvswitch, from Joe Stringer. 2) Initial support for VRF (Virtual Routing and Forwarding), which allows the segmentation of routing paths without using multiple devices. There are some semantic kinks to work out still, but this is a reasonably strong foundation. From David Ahern. 3) Remove spinlock fro act_bpf fast path, from Alexei Starovoitov. 4) Ignore route nexthops with a link down state in ipv6, just like ipv4. From Andy Gospodarek. 5) Remove spinlock from fast path of act_gact and act_mirred, from Eric Dumazet. 6) Document the DSA layer, from Florian Fainelli. 7) Add netconsole support to bcmgenet, systemport, and DSA. Also from Florian Fainelli. 8) Add Mellanox Switch Driver and core infrastructure, from Jiri Pirko. 9) Add support for "light weight tunnels", which allow for encapsulation and decapsulation without bearing the overhead of a full blown netdevice. From Thomas Graf, Jiri Benc, and a cast of others. 10) Add Identifier Locator Addressing support for ipv6, from Tom Herbert. 11) Support fragmented SKBs in iwlwifi, from Johannes Berg. 12) Allow perf PMUs to be accessed from eBPF programs, from Kaixu Xia. 13) Add BQL support to 3c59x driver, from Loganaden Velvindron. 14) Stop using a zero TX queue length to mean that a device shouldn't have a qdisc attached, use an explicit flag instead. From Phil Sutter. 15) Use generic geneve netdevice infrastructure in openvswitch, from Pravin B Shelar. 16) Add infrastructure to avoid re-forwarding a packet in software that was already forwarded by a hardware switch. From Scott Feldman. 17) Allow AF_PACKET fanout function to be implemented in a bpf program, from Willem de Bruijn" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1458 commits) netfilter: nf_conntrack: make nf_ct_zone_dflt built-in netfilter: nf_dup{4, 6}: fix build error when nf_conntrack disabled net: fec: clear receive interrupts before processing a packet ipv6: fix exthdrs offload registration in out_rt path xen-netback: add support for multicast control bgmac: Update fixed_phy_register() sock, diag: fix panic in sock_diag_put_filterinfo flow_dissector: Use 'const' where possible. flow_dissector: Fix function argument ordering dependency ixgbe: Resolve "initialized field overwritten" warnings ixgbe: Remove bimodal SR-IOV disabling ixgbe: Add support for reporting 2.5G link speed ixgbe: fix bounds checking in ixgbe_setup_tc for 82598 ixgbe: support for ethtool set_rxfh ixgbe: Avoid needless PHY access on copper phys ixgbe: cleanup to use cached mask value ixgbe: Remove second instance of lan_id variable ixgbe: use kzalloc for allocating one thing flow: Move __get_hash_from_flowi{4,6} into flow_dissector.c ixgbe: Remove unused PCI bus types ...

ring-buffer: Revert "ring-buffer: Get timestamp after event is allocated"

2015-09-03T12:57:12Z

The commit a4543a2fa9ef31 "ring-buffer: Get timestamp after event is allocated" is needed for some future work. But after adding it, there is a race somewhere that causes the saved timestamp to have a slight shift, and get ahead of the actual timestamp and make it look like time goes backwards. I'm still looking into why this happens, but in the mean time, this is holding up other work to get in. I'm reverting the change for now (which makes the problem go away), and will add it back after I know what is wrong and fix it. Signed-off-by: Steven Rostedt

Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block

2015-09-02T20:10:25Z

Pull core block updates from Jens Axboe: "This first core part of the block IO changes contains: - Cleanup of the bio IO error signaling from Christoph. We used to rely on the uptodate bit and passing around of an error, now we store the error in the bio itself. - Improvement of the above from myself, by shrinking the bio size down again to fit in two cachelines on x86-64. - Revert of the max_hw_sectors cap removal from a revision again, from Jeff Moyer. This caused performance regressions in various tests. Reinstate the limit, bump it to a more reasonable size instead. - Make /sys/block//queue/discard_max_bytes writeable, by me. Most devices have huge trim limits, which can cause nasty latencies when deleting files. Enable the admin to configure the size down. We will look into having a more sane default instead of UINT_MAX sectors. - Improvement of the SGP gaps logic from Keith Busch. - Enable the block core to handle arbitrarily sized bios, which enables a nice simplification of bio_add_page() (which is an IO hot path). From Kent. - Improvements to the partition io stats accounting, making it faster. From Ming Lei. - Also from Ming Lei, a basic fixup for overflow of the sysfs pending file in blk-mq, as well as a fix for a blk-mq timeout race condition. - Ming Lin has been carrying Kents above mentioned patches forward for a while, and testing them. Ming also did a few fixes around that. - Sasha Levin found and fixed a use-after-free problem introduced by the bio->bi_error changes from Christoph. - Small blk cgroup cleanup from Viresh Kumar" * 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits) blk: Fix bio_io_vec index when checking bvec gaps block: Replace SG_GAPS with new queue limits mask block: bump BLK_DEF_MAX_SECTORS to 2560 Revert "block: remove artifical max_hw_sectors cap" blk-mq: fix race between timeout and freeing request blk-mq: fix buffer overflow when reading sysfs file of 'pending' Documentation: update notes in biovecs about arbitrarily sized bios block: remove bio_get_nr_vecs() fs: use helper bio_add_page() instead of open coding on bi_io_vec block: kill merge_bvec_fn() completely md/raid5: get rid of bio_fits_rdev() md/raid5: split bio for chunk_aligned_read block: remove split code in blkdev_issue_{discard,write_same} btrfs: remove bio splitting and merge_bvec_fn() calls bcache: remove driver private bio splitting code block: simplify bio_add_page() block: make generic_make_request handle arbitrarily sized bios blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL) block: don't access bio->bi_error after bio_put() block: shrink struct bio down to 2 cache lines again ...

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-01T03:26:22Z

Pull scheduler updates from Ingo Molnar: "The biggest change in this cycle is the rewrite of the main SMP load balancing metric: the CPU load/utilization. The main goal was to make the metric more precise and more representative - see the changelog of this commit for the gory details: 9d89c257dfb9 ("sched/fair: Rewrite runnable load and utilization average tracking") It is done in a way that significantly reduces complexity of the code: 5 files changed, 249 insertions(+), 494 deletions(-) and the performance testing results are encouraging. Nevertheless we need to keep an eye on potential regressions, since this potentially affects every SMP workload in existence. This work comes from Yuyang Du. Other changes: - SCHED_DL updates. (Andrea Parri) - Simplify architecture callbacks by removing finish_arch_switch(). (Peter Zijlstra et al) - cputime accounting: guarantee stime + utime == rtime. (Peter Zijlstra) - optimize idle CPU wakeups some more - inspired by Facebook server loads. (Mike Galbraith) - stop_machine fixes and updates. (Oleg Nesterov) - Introduce the 'trace_sched_waking' tracepoint. (Peter Zijlstra) - sched/numa tweaks. (Srikar Dronamraju) - misc fixes and small cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) sched/deadline: Fix comment in enqueue_task_dl() sched/deadline: Fix comment in push_dl_tasks() sched: Change the sched_class::set_cpus_allowed() calling context sched: Make sched_class::set_cpus_allowed() unconditional sched: Fix a race between __kthread_bind() and sched_setaffinity() sched: Ensure a task has a non-normalized vruntime when returning back to CFS sched/numa: Fix NUMA_DIRECT topology identification tile: Reorganize _switch_to() sched, sparc32: Update scheduler comments in copy_thread() sched: Remove finish_arch_switch() sched, tile: Remove finish_arch_switch sched, sh: Fold finish_arch_switch() into switch_to() sched, score: Remove finish_arch_switch() sched, avr32: Remove finish_arch_switch() sched, MIPS: Get rid of finish_arch_switch() sched, arm: Remove finish_arch_switch() sched/fair: Clean up load average references sched/fair: Provide runnable_load_avg back to cfs_rq sched/fair: Remove task and group entity load when they are dead sched/fair: Init cfs_rq's sched_entity load average ...

bpf: add support for %s specifier to bpf_trace_printk()

2015-08-28T23:27:27Z

%s specifier makes bpf program and kernel debugging easier. To make sure that trace_printk won't crash the unsafe string is copied into stack and unsafe pointer is substituted. The following C program: #include int foo(struct pt_regs *ctx, struct filename *filename) { void *name = 0; bpf_probe_read(&name, sizeof(name), &filename->name); bpf_trace_printk("executed %s\n", name); return 0; } when attached to kprobe do_execve() will produce output in /sys/kernel/debug/tracing/trace_pipe : make-13492 [002] d..1 3250.997277: : executed /bin/sh sh-13493 [004] d..1 3250.998716: : executed /usr/bin/gcc gcc-13494 [002] d..1 3250.999822: : executed /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1 gcc-13495 [002] d..1 3251.006731: : executed /usr/bin/as gcc-13496 [002] d..1 3251.011831: : executed /usr/lib/gcc/x86_64-linux-gnu/4.7/collect2 collect2-13497 [000] d..1 3251.012941: : executed /usr/bin/ld Suggested-by: Brendan Gregg Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

lib: introduce strncpy_from_unsafe()

2015-08-28T23:27:27Z

generalize FETCH_FUNC_NAME(memory, string) into strncpy_from_unsafe() and fix sparse warnings that were present in original implementation. Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

tracing/uprobes: Do not print '0x (null)' when offset is 0

2015-08-26T13:43:01Z

When manually added uprobe point with zero address, 'uprobe_events' output '(null)' instead of 0x00000000: # echo p:probe_libc/abs_0 /path/to/lib.bin:0x0 arg1=%ax > \ /sys/kernel/debug/tracing/uprobe_events # cat /sys/kernel/debug/tracing/uprobe_events p:probe_libc/abs_0 /path/to/lib.bin:0x (null) arg1=%ax This patch fixes this behavior: # cat /sys/kernel/debug/tracing/uprobe_events p:probe_libc/abs_0 /path/to/lib.bin:0x0000000000000000 Signed-off-by: Wang Nan Acked-by: Masami Hiramatsu Cc: Namhyung Kim Cc: Steven Rostedt Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1440586666-235233-8-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo